• nanostructured polymers;
  • morphology;
  • polyolefins;
  • mechanical properties

A new processing scheme for preparing highly dispersed expanded graphite/polypropylene (PP) nanocomposites has been developed in this study. To improve the degree of dispersion of graphite throughout the PP domains, the solid-state milling has been performed followed by low-temperature melt processing in the range of melting point (Tm) and the crystallization temperature (Tc) of PP. The solid-state milling followed by low-temperature melt mixing could drastically improve the degree of graphite dispersion in the matrix. As a result, the well-dispersed graphite/PP nanocomposite supported by transmission electron microscopy (TEM) exposed a higher degree of plastic deformation and energy to break in the tensile test. The higher degree of graphite dispersion achieved in this scheme was due to the increase of local shear force near the crystalline domains formed during low-temperature melt mixing. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1834–1839, 2013